Can you help me find a replacement for this Diode ?

Thread Starter

Lumenosity

Joined Mar 1, 2017
622
It seems to be an old, outdated Diode but my circuit needs one and I'm having a hard time finding a replacement.
Here is all the data I can gather on it.. The one I took off the PCB looked like a regular Zener dioide to me.

In addition, I don't fully understand this data.

1N1148_Zener.jpg
 

LesJones

Joined Jan 8, 2017
3,498
The data you show in post#1 for the 1N1148 does not agree with other datasheets I found for that device. Your data is for a very high voltage low current diode. The data sheet I have found for a 1N1148 is for a 35 amp 100 volt PIV diode. What is the application that you plan to use this diode for ?

Les.
 

BobaMosfet

Joined Jul 1, 2009
1,850
It seems to be an old, outdated Diode but my circuit needs one and I'm having a hard time finding a replacement.
Here is all the data I can gather on it.. The one I took off the PCB looked like a regular Zener dioide to me.

In addition, I don't fully understand this data.

View attachment 244988
Please provide good image of component- Semitronics doesn't show a 1N1148 in their rectifier datasheet:

1628032707440.png
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
622
The data you show in post#1 for the 1N1148 does not agree with other datasheets I found for that device. Your data is for a very high voltage low current diode. The data sheet I have found for a 1N1148 is for a 35 amp 100 volt PIV diode. What is the application that you plan to use this diode for ?

Les.
It's in a 300watt inverter
Can you give me a link to the datasheet you found with that information please?
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
622
Please provide good image of component- Semitronics doesn't show a 1N1148 in their rectifier datasheet:

View attachment 244993
The listing shown appears to be incomplete. I noticed that.
If you look closely at the page Numbers, the page that would have included this diode is not shown. It skips pages so I believe it is in their datasheets, if they were all included in this listing.
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
622
To assume that the diode in question is the same as the others on the board would be ill-advised.
I understand. but what choice do I have at this point?
I'm not an EE or even that knowledgeable with electronics at this point.
No schematics is available for this device.
The original diode from that location is gone.

It is not possible for me to calculate the necessary value from inspecting the board. I'm not at that level.
Assumptions seem to be all I have in situations like this.

I would say assuming it the same as all the other zener diodes is probably a good bet in this case.
Not always, but in this case due to consistency.
Assuming I assume it is the same and install the same value diode, the diode will be either under the rated voltage and not operate properly or allow to much to pass and likely burn out. In which case I will then try a slightly different range rating.

I would prefer not to make that assumption, but Is there any other way in this case?
 
Last edited:

LesJones

Joined Jan 8, 2017
3,498
The diode shown in post #6 does not look like the diode I found under the part number 1N1148 or the one you found with a PIV rating of 14000 volts. Even if you find the correct diode as you say it is missing you will not know the way to insert it as I can't see any polarity markings on the board. What is the history of the board ? I suspect you may have misread one digit of the part number and if my guess is correct it would be a very common diode. (I think other members may make the same guess.) Check the part number carefully. and report your findings. What evidence do you have that replacing the diode will fix the problem with the board ?
If you trace out the schematic of the board it is possible we could suggest a suitable device.

Les.
 

MrChips

Joined Oct 2, 2009
24,233
There are still many leads for you to pursue.

1) What does the unit do? Make and model? Post a photo of the nameplate.
2) Post photos of full view top and bottom.
3) Post photos of close ups, top and bottom.
4) Attempt to reverse engineer the board.
5) The diode is beside an IC. What is the part number of that IC?
6) At the very least, reverse engineer the circuity around the diode and the IC.
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
622
There are still many leads for you to pursue.

1) What does the unit do? Make and model? Post a photo of the nameplate.
2) Post photos of full view top and bottom.
3) Post photos of close ups, top and bottom.
4) Attempt to reverse engineer the board.
5) The diode is beside an IC. What is the part number of that IC?
6) At the very least, reverse engineer the circuity around the diode and the IC.
It is a TrippLite 300Watt inverter
They shaved off the identification on the IC chip next to the diode unfortunately.

I'm laying out the connections in the area around the diode in KiCad.
I lack the expertise or knowledge to reverse engineer the circuit....but that's why I'm here....trying to absorb knowledge.
Do you think after I do that you could help me?
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
622
The diode shown in post #6 does not look like the diode I found under the part number 1N1148 or the one you found with a PIV rating of 14000 volts. Even if you find the correct diode as you say it is missing you will not know the way to insert it as I can't see any polarity markings on the board. What is the history of the board ? I suspect you may have misread one digit of the part number and if my guess is correct it would be a very common diode. (I think other members may make the same guess.) Check the part number carefully. and report your findings. What evidence do you have that replacing the diode will fix the problem with the board ?
If you trace out the schematic of the board it is possible we could suggest a suitable device.

Les.
Fortunately, the board is marked as to it's orientation.
 

Thread Starter

Lumenosity

Joined Mar 1, 2017
622
Are you're it is not a 1N4148 - one of the most common diodes known in the industry? (Outside the 1N400x series).
I took a loupe and examined the diode as carefully as I could. The markings are rather blurry and not well printed so it's not easy.
I looked at several of them to get the 1N1148

I may remove another or several more just to verify. So far it does look like 1N1148
 
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